Alert archive / Iowa / Special Weather Statements in 2020
Special Weather Statement, NWS Des Moines, IA
NWS Des Moines, IA issued this special weather statement at Oct 12, 2020, 12:21 AM CDT for 4 counties in Iowa. It was in force for 54 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Oct 12, 2020, 12:21 AM CDT (05:21 UTC)
- Expired
- Oct 12, 2020, 1:15 AM CDT
- In force
- 54 min
- Issued by
- NWS Des Moines, IA
Counties Boone County, IA, Polk County, IA, Story County, IA, Warren County, IA
The radar
The Des Moines radar (KDMX), 22 km from the middle of the area, began a volume at 05:22 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 5.4 hours before the alert went out and 245 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 550 J/kg
- Mixed-layer CIN
- -165 J/kg
- Mixed-layer LCL
- 2135 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 240 m²/s²
- 0-3 km storm-relative helicity
- 319 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.6
The text
As transmitted.
749 WWUS83 KDMX 120521 SPSDMX Special Weather Statement National Weather Service Des Moines, IA Issued by National Weather Service Quad Cities IA/IL 1221 AM CDT Mon Oct 12 2020 IAC015-049-099-121-125-127-153-169-181-120615- Polk-Story-Marshall-Madison-Marion-Jasper-Boone-Dallas-Warren- 1221 AM CDT Mon Oct 12 2020 ...A LINE OF STRONG THUNDERSTORMS WILL AFFECT POLK...STORY...WESTERN MARSHALL...NORTHEASTERN MADISON...NORTHWESTERN MARION...WESTERN JASPER...EASTERN BOONE...EASTERN DALLAS AND WARREN COUNTIES UNTIL 115 AM CDT... At 1220 AM CDT, radar indicated strong thunderstorms were located along a line extending from 11 miles north of Boone to near Winterset. Movement was east at 45 mph. Wind gusts up to 50 mph are possible with these storms. Locations impacted include... Des Moines, Ames, West Des Moines, Ankeny, Urbandale, Johnston, Clive, Indianola, Altoona, Waukee, Boone, Norwalk, Pleasant Hill, Grimes, Nevada, Winterset, Adel, Windsor Heights, Carlisle and Bondurant. If outdoors, consider seeking shelter inside a building. LAT...LON 4220 9319 4128 9318 4130 9400 4221 9396 TIME...MOT...LOC 0520Z 267DEG 35KT 4221 9394 4131 9393 $$ rw
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 11, 11:01 PM CDT | Severe Thunderstorm Warning | DMX | Adair, Adams, Cass, Taylor | 59 min |
| Oct 11, 11:52 PM CDT | Severe Thunderstorm Warning | DMX | Adair, Clarke, Decatur, Madison, Ringgold, Union and 1 more | 53 min |
| Oct 12, 12:00 AM CDT | Severe Thunderstorm Warning | DMX | Adams, Taylor | 15 min |
| Oct 12, 12:12 AM CDT | Special Weather Statement | DMX | Calhoun, Carroll, Greene, Humboldt, Pocahontas, Webster | 48 min |
| Oct 12, 12:46 AM CDT | Special Weather Statement | DMX | Clarke, Decatur, Lucas | 44 min |
| Oct 12, 1:31 AM CDT | Special Weather Statement | DMX | Cerro Gordo, Franklin, Hardin | 59 min |
| Oct 12, 2:11 AM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Hancock, Winnebago, Worth | 49 min |
Nearby
Special Weather Statements in Iowa, 2020Every special weather statement in 2020
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.